1. Field of the Invention
The present invention relates to a connector structure of a function-expanding card such as a PC card or memory card to be inserted in the card slot made in a personal computer for expanding the function of the personal computer, and a method of mounting such a connector on an associated printed circuit board.
2. Description of Related Art
Referring to FIG. 24, a PC card 1 is inserted in the card bus connector 2 mounted in a personal computer 7. Specifically the front of the PC card is inserted in the card slot of the card bus connector 2 until its female part 1a is mated with the male part of the card bus connector 2, thereby making a required electric connection between the CPU of the personal computer 7 and the PC card 1.
The card bus connector 2 has a card-ejection arm 3 pivoted about a stationary metal post 8, and the card-ejection arm 3 is operatively connected to a card-ejection lever 4 and operation buttons 5 and 6, which appear outside of the personal computer 7. Thus, the PC card 1 can be removably inserted in the card bus connector 2.
As seen from the drawing, the PC card 1 has a shield 1b on one surface of the female part 1a. The shield 1b can be electrically connected to the grounding conductors in the printed circuit on the computer side.
All contact pieces are press-fitted in the contact holes made in the insulating housing, leaving their soldering tails or leads behind to be exposed out of the insulating housing. It may be possible that some of the contact pieces are loosely fitted, and then the leads of all contact pieces cannot be laid in coplanar relation with the substrate of an associated printed circuit. The allowance of coplanar arrangement of leads is very strict; all soldering leads need to be put in contact with 0.1 millimeter thick creamy solder applied to selected conductors of the printed circuit for reflow-soldering.
As seen from FIG. 25, a male contact piece 9 is mated with a bifurcate female contact piece 1c of the card bus connector 1a. The male contact piece 9 is relatively long, and accordingly the front-to-root length of the bifurcate contact piece 1c is elongated. The rigidity and hence the contact pressure of the bifurcate female contact piece 1c against the male contact piece 9 decreases with the increase of the front-to-root length of the contact piece 1c. This is a major cause for making unreliable contact. Also, disadvantageously the assembling of parts is difficult significantly, compared with use of relatively short contact pieces.
If the bifurcate contact piece is deformed so much within the limited space as to increase the contact pressure of the female contact piece against the male contact piece, the opening size to accomodate the male contact piece in the limited space is reduced accordingly, so that the male contact piece cannot be inserted into the female contact piece with ease. The bifurcate female contact piece is long. Such elongation of female contact piece increases accordingly the manufacturing cost. Also disadvantageously, the resistance to insertion of the female contact piece into the contact hole will increase with the increase of the female contact size, causing a significant disadvantage to the assembling work.